1986 Roller Rocker Head Question???
Thread Starter
Burning Brakes
Joined: Oct 2010
Posts: 1,037
Likes: 28
From: Montclair New Jersey
1986 Roller Rocker Head Question???
I have a 86 coupe with cast iron heads. I am just about to start a cam, lifters, springs, RR, and push rod install. I am installing 1.6 and 1.5 combo rockers. In the instructions with the rockers it says, "I should remove the heads for machine work to clear the new pushrods." I am not installing a high lift cam. All the parts are from Comp Cam. I never read anything about the head work until I opened the RR.
Has anyone had trouble with installing RR on a iron head vette? Should I do the machine work to be safe? If I have to pull the heads I might as well buy a better set. My goal wasn't to buy heads right now but; I don't want to put much money or time into the iron heads.
Any help would be appreciated.....
Has anyone had trouble with installing RR on a iron head vette? Should I do the machine work to be safe? If I have to pull the heads I might as well buy a better set. My goal wasn't to buy heads right now but; I don't want to put much money or time into the iron heads.
Any help would be appreciated.....
Last edited by rrt898; Feb 14, 2016 at 11:10 AM.
Melting Slicks
Joined: Sep 2010
Posts: 2,422
Likes: 202
I have a 86 coupe with cast iron heads. I am just about to start a cam, lifters, springs, RR, and push rod install. I am installing 1.6 and 1.5 combo rockers. In the instructions with the rockers it says, "I should remove the heads for machine work to clear the new pushrods." I am not installing a high lift cam. All the parts are from Comp Cam. I never read anything about the head work until I opened the RR.
Has anyone had trouble with installing RR on a iron head vette? Should I do the machine work to be safe? If I have to pull the heads I might as well buy a better set. My goal wasn't to buy heads right now but; I don't want to put much money or time into the iron heads.
Any help would be appreciated.....
Has anyone had trouble with installing RR on a iron head vette? Should I do the machine work to be safe? If I have to pull the heads I might as well buy a better set. My goal wasn't to buy heads right now but; I don't want to put much money or time into the iron heads.
Any help would be appreciated.....
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Stock heads can handle up to .480 total valve lift before it hits the valve guide nub.
Lobe lift x rocker arm ratio = total valve lift.
Might be a good idea to change to new springs.
And check your valve train geometry by doing the sweep procedure.
Also you cannot use NSA rocker arms with stock heads. They must be SA.
Lobe lift x rocker arm ratio = total valve lift.
Might be a good idea to change to new springs.
And check your valve train geometry by doing the sweep procedure.
Also you cannot use NSA rocker arms with stock heads. They must be SA.
Thread Starter
Burning Brakes
Joined: Oct 2010
Posts: 1,037
Likes: 28
From: Montclair New Jersey
I have read many articles installing RR on an iron head vette. I never read about a pushrod clearance issue. I know if you install an aggressive cam and springs you will need screw in studs. I am not.
Melting Slicks
Joined: Sep 2010
Posts: 2,422
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then installing PR guide plates. Also needing Screw in studs.
Melting Slicks
Joined: Sep 2010
Posts: 2,422
Likes: 202
you did not mention what springs you are using. Weather or not you will need to cut the pockets for larger springs. And reduce the stem for performance VG seals.
Last edited by THE 383 admiral; Feb 15, 2016 at 12:51 PM.
Melting Slicks
Joined: Sep 2010
Posts: 2,422
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Thread Starter
Burning Brakes
Joined: Oct 2010
Posts: 1,037
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From: Montclair New Jersey
Le Mans Master
Joined: Oct 2002
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From: Las Vegas - Just stop perpetuating myths please.
Your wording has us a little confuse rrt. U say now u have a "kit" for your bottom end? Or do u mean u bought a kit for your top end that should work well with your stock bottom end?
Yes please list your parts and what your trying to do. We cant tell whether u have new springs for your new cam or not. Sometimes u need to enlarge the spring pockets for the new wider springs and that would require machine work also. BTW i feel u should change vlv springs every time u change the cam.
Vendors sell a tool to enlarge the push-rod slots in the head for 1.6 rocker arms. I think thats what the Admiral has in his picture and its normally called a "Lewis" tool. U need this because the 1.6 rockers move the p-rod in closer to the head and the stock slots are not long enough. Now if this slot is done right the slot will act as a guide plate and u wont need a guide plate or self-aligning rocker arms. Be careful though as some shops just hog out the slots expecting u to use guide plates - the shop just drilled mine out leaving huge holes because they knew i had guide plates.
Yes please list your parts and what your trying to do. We cant tell whether u have new springs for your new cam or not. Sometimes u need to enlarge the spring pockets for the new wider springs and that would require machine work also. BTW i feel u should change vlv springs every time u change the cam.
Vendors sell a tool to enlarge the push-rod slots in the head for 1.6 rocker arms. I think thats what the Admiral has in his picture and its normally called a "Lewis" tool. U need this because the 1.6 rockers move the p-rod in closer to the head and the stock slots are not long enough. Now if this slot is done right the slot will act as a guide plate and u wont need a guide plate or self-aligning rocker arms. Be careful though as some shops just hog out the slots expecting u to use guide plates - the shop just drilled mine out leaving huge holes because they knew i had guide plates.
Melting Slicks
Joined: Nov 2010
Posts: 2,216
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From: Michigan
edit: to be clear those were 84 corvette iron heads used on a 355 in another car.
Last edited by BOOT77; Feb 20, 2016 at 02:35 PM.
Thread Starter
Burning Brakes
Joined: Oct 2010
Posts: 1,037
Likes: 28
From: Montclair New Jersey
I am starting over. Maybe I should start a new thread?? I want to buy a cam, heads, and rockers that will work with a stock bottom end. I was even thinking of a retro fit roller cam. I have an early 86 block. I am not sure what is too big of a cam for my bottom end?
Melting Slicks
Joined: Jan 2009
Posts: 3,482
Likes: 196
From: folsom california
I have a 86 coupe with cast iron heads. I am just about to start a cam, lifters, springs, RR, and push rod install. I am installing 1.6 and 1.5 combo rockers. In the instructions with the rockers it says, "I should remove the heads for machine work to clear the new pushrods." I am not installing a high lift cam. All the parts are from Comp Cam. I never read anything about the head work until I opened the RR.
Has anyone had trouble with installing RR on a iron head vette? Should I do the machine work to be safe? If I have to pull the heads I might as well buy a better set. My goal wasn't to buy heads right now but; I don't want to put much money or time into the iron heads.
Any help would be appreciated.....
Has anyone had trouble with installing RR on a iron head vette? Should I do the machine work to be safe? If I have to pull the heads I might as well buy a better set. My goal wasn't to buy heads right now but; I don't want to put much money or time into the iron heads.
Any help would be appreciated.....
On cast iron heads, where the push rod passes through, its a narrow slot...this is what locates / guides the push rod it doesn't use guide plates and it doesn't use self aligning rockers. the easy way to check is just rotate the engine by hand and see if there is any interference between the pushrod and the end of the slot...I'm willing to bet that with a relatively mild cam, that even with 1.6 rockers there won't be any interference. If there is, just relieve the end of the slot with a dremel tool or even a round hand file for that matter. It's important not to overthink these things, try the five dollar solution before trying the $1,500 solution, i.e buying and installing new heads.
Last edited by mtwoolford; Feb 18, 2016 at 12:13 PM.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Well if u want a whole top-end package u should provide your block and head casting numbers along with the stamped numbers on the pad in front of the passenger side vlv cover. The block cast number is in the rear behind the drivers side head and the head cast number is under the vlv cover 'bout the middle of the head. This will help identify a 2 bolt or 4 bolt block with cast or forged crankshaft. And most important what compression ratio u may have now and what it will change to with new parts.
Also u may want to start a new this. Well the sbc is the most popular and economical engine to modify. I suggest u shop for the economical/entry level parts for your first effort with this.